Danger from the Deep is an open source World War II German U-boat simulation for Linux/i386 and Windows, but since it uses SDL and the OpenGL API, it should be portable to other operating systems and platforms as well. This game is a tactical simulation to try to recreate the battle of the Atlantic as realistically as possible. The new v0.2 (alpha) release adds improved day and night sky rendering, improved ocean shaders, hydroachoustics, sonar stations, new stations, improved gameplay.